INCREASE OF COPPER TOXICITY TO GROWTH OF CHLORELLA-VULGARIS WITH INCREASE OF LIGHT-INTENSITY

Citation
Fm. Lupi et al., INCREASE OF COPPER TOXICITY TO GROWTH OF CHLORELLA-VULGARIS WITH INCREASE OF LIGHT-INTENSITY, Microbial ecology, 35(2), 1998, pp. 193-198
Citations number
19
Categorie Soggetti
Ecology,Microbiology,"Marine & Freshwater Biology
Journal title
ISSN journal
00953628
Volume
35
Issue
2
Year of publication
1998
Pages
193 - 198
Database
ISI
SICI code
0095-3628(1998)35:2<193:IOCTTG>2.0.ZU;2-8
Abstract
In the absence of inhibitory concentrations of copper, the photoautotr ophic growth of Chlorella vulgaris INET158C at 27 degrees C exhibited a higher specific growth rate and reached a higher maximal concentrati on of biomass, under irradiance of 150 W m(-2), compared with 100 W m( -2). However, when the mineral growth medium was supplemented with CuS O4 (range 40-80 mu M), algal growth was significantly affected at the higher light intensity. In the presence of Cu2+, the increase in dry b iomass was uncoupled from the increase in cell concentration since mor e than 16 autospores gathered together, inside the enlarged mother cel l, suggesting that copper arrested the normal bursting of the mother c ell wall. At the higher irradiance, growth medium supplementation with 80 mu M of CuSO4 led to bleaching of photosynthetic pigments. No grow th was observed, while, under the lower irradiance, growth was only si ghtly inhibited. Results clearly showed that copper toxicity to growth of C. vulgaris was strongly influenced by light intensity. Higher lig ht intensity elicits lethal or sublethal Cu2+ damage at concentrations lower than the threshold level for damage at lower light intensities. Cu2+ may elicit lethal or sublethal light damage at irradiances lower than the threshold level for unpolluted aquatic systems.